Physical Chemistry

Step 1: Meaning of negative deviation from Raoult's law.
Negative deviation from Raoult's law tab hota hai jab unlike molecules ke beech attraction, like molecules ke beech attraction se stronger hota hai. Is wajah se solution ke molecules vapour phase me easily escape nahi kar pate, aur vapour pressure expected value se kam ho jata hai.
Step 2: Identify the type of intermolecular interaction.
Chloroform aur acetone ke mixture me strong intermolecular hydrogen bonding type interaction develop hota hai. Chloroform ka acidic hydrogen acetone ke carbonyl oxygen ke saath strong attraction show karta hai. Yeh unlike molecules ke beech attraction ko kaafi strong bana deta hai.
Step 3: Analysis of the given options.

• (A) Chloroform + Acetone: Correct. Inke beech strong specific interaction hoti hai, isliye yeh negative deviation show karta hai.
  
• (B) Benzene + Toluene: Incorrect. Dono ka nature similar hai, isliye yeh लगभग ideal solution ki tarah behave karte hain.
  
• (C) Ethanol + Acetone: Incorrect in this context. Yeh standard textbook example nahi hai negative deviation ka.
  
• (D) Bromoethane + Chloroethane: Incorrect. Inka behaviour bhi near-ideal hota hai because intermolecular forces kaafi similar hote hain.
  

Step 4: Conclusion.
Isliye jo solution negative deviation from Raoult's law show karega, woh chloroform aur acetone ka mixture hai.
Final Answer:Chloroform + Acetone.

Step 1: Use the formula for depression in freezing point.
The depression in melting point or freezing point is given by
where is the molality of the solution. Therefore,
Step 2: Convert mass of solvent into kilogram.
Mass of acetic acid
Now, molality is defined as
So, moles of ascorbic acid required are
Step 3: Calculate molar mass of ascorbic acid.
Ascorbic acid is . Its molar mass is
Step 4: Calculate the required mass.
Mass of ascorbic acid moles molar mass
Step 5: Conclusion.
Hence, the mass of ascorbic acid required to produce the given lowering in melting point is 5.077 g.
Final Answer:5.077 g.

Step 1: Recall the definition of an ideal solution.
An ideal solution is a solution that obeys Raoult's law over the entire range of concentration. In such solutions, the intermolecular forces between unlike molecules are nearly the same as those between like molecules. Because of this, mixing occurs without any significant heat change or volume change.
Step 2: Enthalpy change of mixing.
For an ideal solution, the energy required to separate molecules of the pure components is almost exactly equal to the energy released when unlike molecules interact after mixing. Therefore, there is no net heat absorbed or evolved. Hence,
Step 3: Volume change of mixing.
In an ideal solution, since the sizes and interactions of the molecules are similar, the total volume after mixing remains equal to the sum of the individual volumes before mixing. Thus, there is no contraction or expansion in volume. Hence,
Step 4: Conclusion.
Therefore, the correct condition for an ideal solution is
Final Answer: .

Step 1: Write the formula of molarity.
Molarity is defined as the number of moles of solute present in litre of solution. Therefore,
Here, the solute is , its mass is g, and the volume of solution is mL.
Step 2: Calculate the molar mass of .
The molar mass of sodium hydroxide is calculated as follows:
So,
Step 3: Calculate the number of moles of .
Thus, the number of moles of present in the solution is mol.
Step 4: Convert volume into litres and find molarity.
Given volume of solution mL
Since,
therefore,
Now,
Approximating to two decimal places,
Step 5: Conclusion.
Hence, the molarity of the given solution is . Therefore, the correct option is .
Final Answer:0.42 M.